Crown Race . . . . Am I going to die a horrible death ! : )

I was making a lightweight crown race converter, basically a crown race for running a standard 1-1/8" fork in a tapered headset (1-1/8" to 1-1/2")

I was about to hit the print button for an aluminium print (I'm using Shapeways for 3D printing) . . . but then I had a thought, a crown race for an integrated headset serves little other purpose these days other than to seat the lower bearing - long gone are the days when a crown race was an actual race surface for the lower (non-cartridge) bearings to run on. It's a kind of vestigial remnant in these days of integrated headsets.

So I was thinking - in the pursuit of pathological weight weenie gram saving - does it really need to be made from aluminium or could it be made from a tough plastic like nylon ?

If I print it in nylon it would easily beat extralite and Tune with regards to weight - of course the savings are minimal with something as small as a race, but hey, this is the weight weenie forum, a place where people shave their eyebrows for a more efficient face

Anyhow, if anyone has any input I'd be happy to hear it, otherwise I'm going to take my life in my hands and hit the print button on nylon !!

P.S - if this works out - and I don't die - then I'll leave the 3D file up on Shapeways and anyone is free to print one out for themselves - at your own risk !!

Yeah, you can already buy plastic ones. I have the Cane Creek one. Like you say, there is no need for it to be metal. You can also put a split in it so that fitting and removal is easy.

The split (on metal CR) is very handy for removal/reinstall, so that's a great idea. Unsure if that adversely affects a nylon one. (?) At least nylon could be cut off easily enough for removal I suppose.

Yeah, you can already buy plastic ones. I have the Cane Creek one. Like you say, there is no need for it to be metal. You can also put a split in it so that fitting and removal is easy.

I was going to put a split in the ring, but I've never really had an issue hammering races onto a fork, I just use a tube of some kind and give it a few good solid hits and it's on . . . I also thought that being made from nylon it wouldn't hurt to have the little extra mechanical integrity of being a solid ring.

The split (on metal CR) is very handy for removal/reinstall, so that's a great idea. Unsure if that adversely affects a nylon one. (?) At least nylon could be cut off easily enough for removal I suppose.

[Shaving eyebrows as we speak.]

Yeah, that was my thinking too, a solid ring would lend nylon a little more mechanical integrity and it would be easy enough to cut off if it needed taking off (they aren't expensive to print, so I might order a few to throw into my spares box).

On the subject of facial hair, I'm working on some quick release eyebrows, so you can simply unclip them before getting on your bike.

I trimmed off the green area (from the above image in my previous post) - the only downside I can see is that the green area acts as a sort of barrier - keeping dirt and grim off the lower part of the bearing . . . . ?

I also tapered the top area (blue in the above image in my previous post) down to where it meets the steerer tube (the yellow band).

I also thought that being made from nylon it wouldn't hurt to have the little extra mechanical integrity of being a solid ring.

But you're going to put holes in it?

The ring is in compression and is prevented from expanding outward by the inner lip that protrudes up into the recess on the bearing. A split in the ring will make no difference to the performance at all.

Drilling away so much of the material on the other hand, might. And for what gain? A weight saving of literally a few grams?

Plastic ones already do the job perfectly at little cost. This part does not need to be reinvented.

No opinion on your particular design, but Cane Creek 10 series crown race is polymer.

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Yes and the 10 series is their "economy" model. It came on my bike. The plastic crown race busted up and the whole thing imploded into the headtube. Ended up having to push my bike out and call my wife to come pick me up (I had ridden to the trail from my house). Replaced it with a 40 series with a steel race. I'll take the extra weight.

There are two types of people in this world:
1) Those who can extrapolate from incomplete data

Replaced it with a 40 series with a steel race. I'll take the extra weight.

I was thinking I might get the race printed in nylon, aluminium and steel (weirdly steel is much cheaper to print than aluminium?), I expect even when printed in steel it will be as light or even lighter than a standard aluminium (conversion) race . . . . this is really just a weight weenie experiment so it might be useful to see how all three materials turn out.

Yes and the 10 series is their "economy" model. It came on my bike. The plastic crown race busted up and the whole thing imploded into the headtube. Ended up having to push my bike out and call my wife to come pick me up (I had ridden to the trail from my house). Replaced it with a 40 series with a steel race. I'll take the extra weight.

There has to be thousands of 10-series headsets out there in the wild at this point. I'm not aware of a recall, and that series isn't new (unless the polymer portion is a recent change). Do you have any other details about the failure? Was it over-torqued somehow? Are you literally saying it was in pieces? I'm wondering if low temperatures were a factor.

I'm not defending, nor criticizing anything here, but you'd think fear of litigation alone would ensure that the polymer used in this case was deemed "safe". (?)

There has to be thousands of 10-series headsets out there in the wild at this point. I'm not aware of a recall, and that series isn't new (unless the polymer portion is a recent change). Do you have any other details about the failure? Was it over-torqued somehow? Are you literally saying it was in pieces? I'm wondering if low temperatures were a factor.

I'm not defending, nor criticizing anything here, but you'd think fear of litigation alone would ensure that the polymer used in this case was deemed "safe". (?)

[Sorry for overuse of question marks in this post.]

I don't think it was over-torqued, it hadn't been touched and the bike is a 2014 model and it happened this summer so it wasn't cold either. I don't recall if it was in several pieces or if it split and collapsed in, I just recall it being down inside the head tube. I think it probably split and then as I rode, it worked itself inward until it fell in as the bike was feeling a little odd and that increased to wtf is going on. Yes, I should have stopped and did a complete inspection but I was trying to figure it out from how the bike was handling at first.

I did a little googling and found a few reviews where people had problems with the plastic but in their cases, it did sound like poor installation.

Since the 40 is basically the same as the 10 but more expensive with the steel race, I'd say the plastic of the 10 is about saving cost, not weight. But you're right, haven't seen a recall and I don't see a lot of reports of failure. I'm not a real hard rider so I wouldn't think that I bashed the fork hard to possibly cause damage.

There are two types of people in this world:
1) Those who can extrapolate from incomplete data

with plastic 10 series it was/is easy to install it upside down. i think it is easy to install wrong because all you do is place it there by hand and you are good to go and the sides have a similar look.

I was making a lightweight crown race converter, basically a crown race for running a standard 1-1/8" fork in a tapered headset (1-1/8" to 1-1/2")

I was about to hit the print button for an aluminium print (I'm using Shapeways for 3D printing) . . . but then I had a thought, a crown race for an integrated headset serves little other purpose these days other than to seat the lower bearing - long gone are the days when a crown race was an actual race surface for the lower (non-cartridge) bearings to run on. It's a kind of vestigial remnant in these days of integrated headsets.

So I was thinking - in the pursuit of pathological weight weenie gram saving - does it really need to be made from aluminium or could it be made from a tough plastic like nylon ?

If I print it in nylon it would easily beat extralite and Tune with regards to weight - of course the savings are minimal with something as small as a race, but hey, this is the weight weenie forum, a place where people shave their eyebrows for a more efficient face

Anyhow, if anyone has any input I'd be happy to hear it, otherwise I'm going to take my life in my hands and hit the print button on nylon !!

P.S - if this works out - and I don't die - then I'll leave the 3D file up on Shapeways and anyone is free to print one out for themselves - at your own risk !!